[declan]

Are all your options vested? Did the company retain the right to repurchase?* Why exercise the options now? Can you afford to lose that cash if you the shares become worthless post-exercise? Can you sell or transfer your options or pledge as collateral to a loan?

IMHO you should seek advice from a lawyer specializing in this area (who is also familiar with the tax implications).

* Lawyers often tell founders something like: "Typically, the Company retains a right to repurchase unvested shares at cost upon termination of employment. During the period that the shareholder continues to be employed or otherwise provide services, the repurchase right expires according to a vesting schedule."

[optionadvice]

All options are vested. Not entirely sure. I could have afforded if I had purchased them earlier this year, but the tax consequence of buying them now is impossible it seems (everyone is saying that without an 83b and purchasing them earlier this year, I basically would have to pay the tax on the full value now). I will reach out to a lawyer soon. Figured HN would have plenty of people who had been there before and willing to give some brief advice/info.